The following invention concerns a stopper for a beverage container such as in particular for a beer keg, a tapping assembly comprising the stopper, and the beverage container itself that is closed off by the stopper.
It is known to provide beverage containers such as beer kegs, including also the so-called party kegs having a fill volume of usually 5 or 10 liters, with a fill or outlet opening that, during storage of the beverage container, is tightly closed off and is then provided with a tapping assembly when the beverage container or the keg is to be used. These outlet openings are provided with a closure that usually is removed and exchanged for a dispensing device such as an outlet socket or a tap when the beverage is to be consumed. Alternatively, closures are known also which constitute at the same time a stopper as well as a tap.
Such a closure is disclosed, for example, in DE 21 2005 000 063 U1. Here, a closure in the form of a tap or stopper for a beverage container such as a beer keg is disclosed whose main task is to avoid the disadvantageous effect of oxygen entering the interior of the container. This is achieved in that the tap has at least one injection-molded plastic part that is doped with a scavenger. Herein, the tap can be comprised of at least two parts that are movable relative to each other by means of which a dispensing opening can be closed off, wherein at least one of the parts is the scavenger-doped plastic part.
While this closure has the task of keeping oxygen away from the beverage in the container, the stopper that is disclosed in DE 10 2007 0 29 450 A1 has the function of an overpressure safety means. Here, reference is also being had to party kegs that are constructed as three-part seamed closure kegs, comprising a body with a welded longitudinal seam and bottom and top that are connected to the body by a seam. Against a pressure increase by CO2 development past a certain limit value, an overpressure safety means is to be provided by means of which, in case of an unexpected pressure increase, pressure can escape from the container to the exterior before overloading of the seamed connection or bursting of the container can occur. Accordingly, a stopper that is insertable into an opening of the container in a seal-tight way is disclosed herein which has a passage that is closed seal-tightly by a film that forms a seal that yields and opens the passage opening when a certain pressure is surpassed.